something wrong with imessage?

So around midnight I had gotten a text message from my friend, but I had never gotten the notification for it (my notifications are set to be on) so I went into iMessage to look at the message, but the entire conversation with my friend turned up to be completely blank. Confused, I exited out of my messages and tried to go back on with no such luck. Slightly frustrated, I just turned my phone off for about a minute thinking maybe it would fix itself if I did that. No such luck happened and when I turned my phone, every single one of my messages were gone. I personally hate deleting text messages so this wasn't of my doing. This problem occurred back in February, with all my texts deleting themselves, and I was never able to figure out why or how to get them back. Now I have started a few conversations since on my phone yet I have not received a single notification for replies. I have received notifications for my other apps so it's not my wifi or anything like that affecting my non notifications.

I have an iPhone 5c with update ios 8.3